Even murderers need friends. The world is an awfully lonely place for everyone, but especially for a jailed convict.

Kim Zupan’s passionately arresting debut novel, “The Ploughmen,” is about isolation and the ghosts of one’s past. It’s also a painstaking map of those who feel imprisoned, whether physically or emotionally.

A brutal killer who dismembers his victims in order to make their bodies unidentifiable is in a Montana prison. John Gload isn’t a newbie — he has killed a bunch of people over the years, and he’s now in his late 70s. Valentine Millimaki is a young deputy who works the night shift.

Gload and Millimaki spend a lot of time talking and discover, unsurprisingly, that they share some common history involving troubled boyhoods. One has taken the path of justice. The other has chosen the darker road.

Millimaki realizes how easy it would be to step into Gload’s shoes: “The distance from reason to rage is short, a frontier as thin as parchment and as frail, restraining the monster. It was there in everyone, he thought. It was there in himself. A half-second of simple blind fury and the hatchet falls down.”

THE PLOUGHMEN

By: Kim Zupan.

Publisher: Henry Holt, 272 pages, $26.

Review: An elegiac novel that juxtaposes beautiful sentences with dark thoughts and actions.

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The deputy carries around his own personal demons, going back to when he was a child and found his mother’s body after she killed herself.

Even though Zupan’s novel deals with grim topics, he plows the depths of grief and numbness with such a concentrated dedication that the prose is a character in itself. His sentences are unleashed in a furious splendor, such as in this scene when the deputy is driving:

“He dangled his wrist atop the steering wheel and stared out broodingly at an outlandish sky, long flaming celestial mesas and reefs and the copper half disc of the sun diminishing beyond stagecraft mountains in the west and sucking after it, into that far void, minute birds the color of embers.”

Millimaki is suffering from lack of sleep; from a wife who is distancing herself from him and decides to leave him for someone else; from becoming a living ghost to himself and the woman he loves. He shares some of these pains with the prisoner. He unburdens himself but is still burdened.

Those who are in prison aren’t the only ones who are confined and limited. The world itself can be an oppressive place to live in.

“The world for these men was reduced to floor, ceiling, walls, and bars, and his own differed little — an unfixed cubicle of solitude that, like a carapace, went with him everywhere.”

“The Ploughmen” is bleak and brilliant — the best kind of book.

Michele Filgate is a freelance writer and independent bookseller who lives in Brooklyn.